1. Field of the Invention
This invention relates to implantable devices for pacing and, when necessary, defibrillating a heart.
2. Description of the Prior Art
Heart defibrillation is currently performed by the discharge of a powerful voltage pulse between two electrodes. The electrodes are placed so the discharge takes place over the heart or a large part thereof. The energy in a pulse amounts typically to several to a few dozen joules.
The large energy required in the defibrillation pulse has shortcomings. For implantable devices with both defibrillation and pacemaker functions, i.e. devices designed to normally operate as pacemakers, the high energy consumed in defibrillation shortens the life of the apparatus considerably. The powerful energy discharge also has certain adverse effects on the organism.